Cooling x-ray tubes

ABSTRACT

551,895. Cooling R÷ntgen-ray tubes. GRAVES, E. B. Sept. 11, 1941, No. 11651. [Class 98 (i)] [Also in Group XL] In a liquid-containing cooling jacket for an X-ray tube means are provided for causing circulation of the liquid to conduct the heat to the wall of the jacket, and also means for causing a flow of cooling fluid against the external surface of the jacket. As shown, the tube is mounted in a shell 5 filled with oil or other insulating and cooling liquid, which is circulated by an impeller 14 operated by a motor mounted on a cap closing the end of the shell. A tubular member 18, which may be of lead or bakelite, serves to guide the liquid flowing towards the impeller into contact with the tube, and that returning from the impeller into contact with the wall of the shell; it serves also as a screen for the rays. The shell 5 is surrounded by a metal jacket 20, between which and the shell air is caused to flow by a fan or blower 23 in a casing 24 mounted on the jacket.

Oct. 14, 1941. E. B. GRAVES COOLING X-RAY TUBES Filed Feb. 25, 1940FIG-l gal/7% INVENTOR DWARD B. GRAVES ATTOR FIG-2 NEYE Patented Oct. 14,1941 .to Picker IX-Ray Corporation Waite Manu- "facturing Division,lnc.,Cleveland, Ohio, a corporation of Ohio 'Avpiplication Februany 23, 1940,Serial No. 320,323

'6 Claims.

This invention relates to cooling vof 'i Xe'ray tubes.

One Object of the invention isto lprovide'improved means for cooling anX-ray' tub adapted rapidity so that neither the tube ncrits'mountvingiparts or iconnectionsrea'ch undesirable high mosphere, asthe case may be.

A further object is "to provide an improved X-ray tube mount 'ofig'en'e'rally standard' fo'rm with the tube enclosed in a shell 'withinwhich an'insulating and more or less heat conducting fluid iscirculated, said shell being surrounded by an enclosing c'a'sin'gforming 'two 'closely contiguous 'walls," and 3 Hence an annularchamber, through which air 'or ethersuitable fluid may be caused to"flow ffor 'cooling 'pur'p'ose's.

Further objects of the invention are in'part 'obvious'an'd in; part"willappear mor detail hereinafter.

In the drawinggwhich irepresents one- 'suitarivle embodiment of i theinvention, Fig. 1i's= a centr al "longitudinal section; Fig. :2 isan rend view from the right in'Fig. 1; Fig. 3"-is" asectional-elevationon'appr'oximately th line 3' 3, Fig. 1; amil "The 'X='ray tube -itselfrequires no extended description because it is' of usual form, includingthe hollow glassbody l in which is 'mounted the anode 2, usuallyarheeivypiece "Of cGpperei-ther hollow' or solid," carrying theinlafd' target 73, the outer 'end of said -:a'n'o'cle extending outthrou'gh oneof:the"endsof the T'ho'llowigla'ss body. The anode of course is an"excellent "conductor'o'f the heat producedjwhich is dissipated l'argely"from that end of the anode Whichextiands beyond -the glass body.

The tube" body is 'suitablymiount'e'd in' anenclosing shell, markedgenerally 5, usualy made I of aluminum, an aluminum alloy,' orother-"suitable light material, provided on oneisid'e,"'opposite thetarget 3, with the usualwind'ow "6, and on its to dissipate thegenerated heat with sufiioient -;55

-fhavingcavities 8nn whichtane inserted-terminals '(notishown)connectedrto theifl'ead'W-iresT-mr the tubercircuits.

Erie and i of ithe shell supports the .usual .cexipans'ion 'idevice,such' as the frsylphon :b'elIews F9, Farranged ito'compensateforvariations; in volume 10f the fluid iwi'thin'fth'e fshellTas :the result :of changes 'in temperature for tone T635011 :orsanother. Frequently such expansion :chambers :haverbeeni'mounte'd'onezin each endrof the tubu- 'la'rishllfibut according to theipresentninvention but a single r'expansion z'device iis employed, theother fend iio'f ithe: shell rserving 'tofisupport fluid'circutatingzmeansas will 'moreiffullylappear hereafter.

The tube, of course, Sis rigidly --but rremovably mountedwithin theshell, so tthatwhetargettis 'in its :central ilongitudinal faxis 1 andopposite "the centerio'f the window -6. Forthis purpose "the oppositeends of -th tube-fiaremounted in sup- .p'orts' 0, l I iattac'h'e'drto'the' stationary 'Ish'elr 'or to a 1 part :fix'ed ith'eretowsuch -:asto the sleeves 1'2 into'whichtnewire carrying terminals are in- :serted.Any Rather "suitable 'Itub'e supporting 125 .means m ay :fbe employed.

:The Shell "chamber l3 i's'f-fi'lled 'with 'a 1 suitableinsula'ting'liqui'd which iaiso is a more "or less :efii'cient heatfcarrier,"'such as a suitableroil, and ftol'more' rapidlyfdissipate'ithe' heat means is prowithin chamber l3. The meansshownicompris'es any "suitable oil movin-g device, such as the imp'ellerI4imounted-on the shaftI 5= o r an'operatin device, such asan electricmotor IB, rigidly imounted withln a'closing cap H 'on'on'e end of fth'rtubular sh'ellti. The motor and "impeller preferably are"mounted-'coaxially =with the "shell -axis,:a'nd="n1eans :isrprovided' 'wherbysaid imqaeller, when opeiatingfikeeps' the entire =b'0dy of 0 the foilcohstantly in' mo'tion, circulating an of iitgatfone time*ioranother,"=into close orihtimate heat conducting relation with the shellwall 5, e'so that -th-e heat' carried by thecoil may be abisoribed byandthen 'radiated from said wall and thus "become dissipated.

The i'rneans shown tor "this purpose is a tubular shield or guidelB,'-which-*may"be made of "lead, Bakelite 'or othe'r 'silitfiblematerial, I but is rhere a'ssumed to' b e maiie of -lead- 'v'ri th anopen- "5 ing for win'dow ii) so as to serve not=only'to assist indirecting the 'flow "of th'e "heat dissipating 'iiquidflbut also as =a'shi'eld for the 'X-rays generated. Tube is inimovablyrmounted in thefshell insany'isuitable manner. A-s shown in Fig.

opposite side with hollow tubular extensions F155 3 its'upper eurvedsurface:is held tightlyagainst the inner surface of the shell wall tothe left in Fig. 1 through the annular space between shield I8 and theshell, finally re-entering the other end of shield l8 and again flowingto the right along the outer surface of the X-ray tube I and its anode2.

As a consequence of the described liquid flow,

the liquid absorbs the heat generated by and within the tube l, and thatconducted by the anode 2, and carries and gives it up to the metal ofthe shell, from the outer surface of which it may be dissipated in anysuitable manner, fins, ribs, knobs or other devices (not shown) forincreasing the area of exposed heat radiating surface of said shell ofcourse improving efficiency.

Under some circumstances improved cooling effects are secured by theprovision of means for dissipating the heat from the shell wall by theuse of another fluid.

In the arrangement shown the shell wall is surrounded by a thinmetal'jacket 20, made from steel or other suitable material shaped ingenerally tubular form, with openings where necessary, such as at thewindow 6. This jacket is closely spaced from the outer surface of theshell, but is rigid with relation thereto. For example, the jacket endsmay b provided with short spacing legs 2! separated by Openings for aircirculation.

As shown in Figs. 1 and 3, any suitable means is provided for forciblymoving air through the annular space 22 between shell 5 and jacket 20,such as the fan or blower marked generally 23, enclosed within a casing24 mounted upon the jacket, and in which casing is also enclosed asuitable electric driving motor 24a for the blower, the latter beingadapted when operated to receive atmospheric air through the inlet 25and impel it through the blower outlet 25a into and along the annularcavity 22 toward both open ends of the shell, through which it isdischarged to atmosphere.

In operation, therefore. assuming the shell 5 to be filled with oil andthe X-ray tube to be in operation, both motors I6 and 24a are started.

During operation all of the heat generated in or by the X-ray tube isabsorbed by the circulating oil, which carries it by convection to thewall of the shell 5, from which it is either dissipated directly byradiation or is transmitted to the air current flowing along its outersurface, which by convection carries the heat away to the outside air. a

For simplicity of illustration the circuit wires for th two motors areomitted, but it will be understood that they ar connected to areceptacle 30 to which the usual attachment plug (not shown) may beconnected.

In X-ray tubes of this character as heretofore mounted and operatedwithout cooling means, but

with oil within the shell, it has been found that within ten minutes ofnormal operation the temperature rises to above 500 F., whereas with thepresent cooling system in operation the temperature does not exceed 200F. or less and may be maintainedat that value throughout operation ofthe 'tube over an indefinite period. As a consequence neither the tubenor its mounting parts are subjected to an undesirable temperature andtube operation may be carried on at full capacity for extended periodsof time without either injury to th apparatus or discomfort to operatoror patient. Other advantages of the invention will be apparent to thoseskilled in the art.

What I claim is:

1. In combination, a hollow shell provided with a chamber, an X-ray tubemounted in said chamber and spaced from the wall thereof, said shellproviding one large liquid-tight chamber adjacent said tube and withoutexternal passages, said chamber being filled with a heat conductingelectric insulating liquid, an impeller within said chamber for causingmotion of said liquid to conduct the heat produced by said tube to theshell wall for dissipation thereby, means mounted on said shell foroperating said impeller, a hollow casing enclosing said shell and spacedtherefrom to form an annular cavity through which air may flow forabsorbing heat from the shell wall and dissipating it by convection, andmeans mounted on said shell for causing air flow through said cavity.

2. In combination, an elongated hollow shell provided with a chamber, anX-ray tube mounted in said chamber and spaced from the wall thereof toprovide an annular elongated space between the walls of the shell andtube, said spac being filled with a heat conducting electric insulatingliquid, a tubular guide in said annular space, an impeller mounted inone end of said shell for causing circulation of said liquid throughsaid elongated space in one direction Within and in the other directionoutside of said guide, a hollow casing enclosing said shell and spacedtherefrom to form an annular cavity through which air may flow forabsorbing heat from the shell wall and dissipating it by convection, andmeans for causing air flow through said cavity.

3. In combination, an elongated hollow shell provided with a chamber, anX-ray tube mounted in said chamber and spaced from the wall thereof toprovide an annular elongated space between the walls of the shell andtube, said space being filled with a heat conducting electric insulatingliquid, a tubular guide in said annular space, an impeller mounted inone end of said shell for causing circulation of said liquid throughsaid elongated space in one direction within and in the other directionoutside of said guide, a hollow casing enclosing said shell and spacedtherefrom to form an annular cavity through which air may flow forabsorbing heat from the shell wall and dissipating it by convection, andair moving means mounted upon said casing with its outlet communicatingwith said annular cavity for directing a current of air therethrough.

4. In combination, a hollow heat-conducting shell providing aliquid-tight chamber, an X-ray tube mounted in said chamber and spacedfrom the wall thereof, said shell providing one large chamber adjacentsaid tube and without external passages, said chamber being filled witha heat conducting electric insulating liquid, an impeller within saidshell and immediately adjacent said tube for causing motion of saidliquid to conduct the heat produced by said tube to the shell wall fordissipation thereby, means for operating said impeller, and means forcausing a flow of cooling fluid against the external surface of saidshell.

hollow heat-conducting shell providing a liquidtight chamber, an X-raytube mounted in said chamber and spaced from the wall thereof, saidshell providing one large chamber adjacent said tube and withoutexternal passages, said chamher being filled with'a heat conductingelectric insulating liquid, an impeller within said shell andimmediately adjacent said tube for causing motion of said liquid toconduct the heat produced by said tube to the shell wall for dissipationthereby, and means for operating said impeller.

EDWARD B. GRAVES.

